Electrooptical system



P 1930- J. w. HORTON 1,775,241

BLECTROOPTICAL SYSTEM Fi led May 25, 1929 2 Sheets-Sheet 2 Was 24 //VVENTO/P u! (Ha/emu A TTOHNE) Patented Sept. 9, 19 30,

1105mm w. xoazron, or cmamon,

or wholly I the field of view, developin YORK Application fled Kay 25,

This invention relates to electro-optical An object of the resent invention is to provide an improve television system especially adapted to theviewing of extended scenes such as, for example, a ball-game or a streetscene where the field scanned is partly at a distance-from the scanning mechanism. Amore limited object of the invention is to provide a new and improved apparatus for electrically duplicating .tion picture films.

Prior to this invention it had been proposed to accomplish the television of an extended scene by taking a motion picture of and scanning the exposed film, transmitting electrical currents representative of the scanning to a receiving station, exposing and developing another motion for projection on a screen, all in one-continuous process, so that the delay introduced by the record making becomes a'negligible time factor. According to the present'inve'ntion, the electrical transmission of separate por:

'tions of such a film simultaneously over a plurality of transmission channels is accom plished,thereby making possible the use of a simplified type of transmission channel and one which is readily available in the commercial telephone plant. y p

A feature of the invention'is the storing of signals received from-a plurality of simultaneously operating transmission channels to control the projection of successive images for the proper intervals to produce motion "pictures-at the receiver.

' Another feature of the invention is the simultaneous scannin of a plurality of frames of the develo e film to produce image currents for transmission over an equal num-.

ber of transmission channels forexposing a like number of frames of a motion picture film blank at the receiver. In the example of practice selected for illustrating the'inven-,

tion, scanning discs are employed having a pluralityof sets of spirally arranged apertures' equal to' the number 'of frames to be scanned 's:imultaneously. Light valves prefpicture' film at-the receiver ordinary Qumran STATES P'ArE-NT "ToF-FI B I llassacnusn'rrs, assr'o'non 'ro BELL TELEPHONE Q LABORATORIES, INCOBPOBATED OF N EWCYOBK, N. Y., 1 CORPORATION OF NEW mncrnoor rrcan srsrnm 102s. swarm). 385,855.

A more detaileddescriptioii of the invention will now be given having reference to the accompanying drawings.

Fig. 1 is a schematic circuit diagram of a .system, embodying this invention,

Figs. 2 and 3 show'details respectively of v ,the transmitting and receiving apparatus of Fig. 1. I

Fi 4 is a side view. of the scanning'disc used. 0th at the transmitter and receiver. Fig. 5 is'an alternative light control arrangement for use at the-receiver.

Identical elements in the several figures are identified by like reference characters.

Referring now to Fig. 1 transmitting apparatus T is associated with receiving apparatus R'by a plurality of separate electrical transmission channels; In the arrangement illustrated three channels, L, L and'L are, employed. Each of these channels may com- I prise a physical transmission line, a carrier channel, or a radio link or combinations thereof. Each electrical channel originates in a photoelectric cell'at the transmitter and terminates in a light valve at the receiver.

Transmitting apparatus T, as illustrated in Fig. 2, comprises means for exposing a motion picture film in accordance with a scene, an image of which is to be produced at the receiver, immediately thereafter developing and fixingthe film, and then scanning the film to produce image currents. The unexposed film' on reel' ll is fed through an motion picturevcamera 12 down to a developing tank 13'anda-fi-xing tank 14, then 'up over guide wheels 15' and 16 between which it is exposedto the scanning light beam 1.7,

and finally down to the take-up reel 18. The

tion for the exposure of successive frames. The motion through the tanks 13 and 14 is preferably at a uniform rate. The motion across the scanning beam 17 however, is intermittent, groups of three frames each being scanned simultaneously; v

17 is lamp 19' backed by reflector 20 and directed to the film by the lens system 21. An image of each group ofthree frames is formed by the lens system 22 upon the lefthand face of scanning disc 23; The disc 23 is driven by suitable motor 24 at a speed suitably related to that of the film moving mechamsm. I

The disc 23 is illustrated more in detail in Fig. 4 and comprises three sets of spirally arranged scanning apertures 25. Each set of apertures is used to scan a separate frame of the group of three frames exposed simulta neously to the scanning beam 17. These frames are represented in Fig. 4 by the dotted rectangles 26, 27 and 28. p The light passing through the apertures of the outer spiral after reflection by mirror 29 is directed by lens system 30 to photoelectric cell 5. The light from the apertures of the middle spiral is directed by the lens system 31 to photoelectric cell 6. Light from the apertures of the inner spiral is reflected by mirror 32 and directed by the lens system 33 to photoelectric cell 7. Thus each separate frame of a group of threeframes is scanned simultaneously and produces image currents in each of the separate channels L, L and L. I

A blank space is left between the first and last apertures ofeach spiral-to prevent the passage of light to the photoelectric cells 5, 6 and 7 while the film'ismoving across the light beam 17 between group scannings;

During the operation of the transmitting apparatus T the exposure of a frame in themo- 5 tion' picture camera 12 takes one-third of the time that is devoted to the scanning of each frame for the product-ion of image currents; At the receiver the apparatus R provides for the exposure of amotion picture film,

the development and fixing of the film and its projection at the proper rate to produce a 'motion' picture on the screen 34 of Fig. 3.

r A suppl of unexposed film on reel 35 is fed by suita lei driving'mechanism36 through an exposing chamber 37 after which it is .passed through developing tank 38and fixing tank 39 to a motion picture projector 40. Three frames are exposed simultaneously in accord ance with the image currents received over the three transmission channels L L and L The image currents from channels L 1 andL? respectively are impressed upon light valves :8, 9 and 10 respectively, to control the intensity of the light from sources: 41, 42 and 43 respectively, illuminating atany instant rectangular areasof scanning v tangle produced by light from source 41 cor- The source of light for the'scan'ning beam] responds to the outer spiral of apertures of disc. 44, that produced bysource 42 to the middle spiral and that produced by source 43 to the inner spiral. The light from source 41 is focused by lens 45 on the aperture of light.

valve 8. vLens 46 focusses an image of the light valve aperture in a plane in the vicinity of lens 47 which in turn produces an image of anaperture in screen 48 upon the righthand face of disc 44 after reflection by mirror'49. The lens system for directing the light from sources 42 and 43 is identical with that just described except that norefiecting mirror is used with the source 42 and mirror 50 is used with the source 43. An image of that portion of the left-hand face of scan:

tures, causes each elemental area of the film to be exposed to the proper degree to produce an image after development.

The exposed film is .developed in tank 38 and fixed in tank 39, after which it is exposed to light from the arm 53 directed by lens 54 and imaged by lens 55 upon the screen 34. By means of the intermittently moved film and ordinary interrupter disc 56 of the motion pictureprojector 40, a motion picture is reduced on the screen 34.

ny suitable electrical transmission channel may be used between the photoelectric cell and the. light valve. As illustrated in 1 a carrier system is employed. The image currents from photoelectric cell 5, are used to modulate in modulator M carrier currents from source 0 These modulated carrier currents are transmitted through transmitting filter TF over line L to receiving filter RF and amplifier A from the output of which they-are impressed upon light valve 8. Similar apparatus is used in the other channels. A channel of this kind is disits closed in Patent No. 1,606,227 issued November 9,1926, to Horton, Ives and Long.

1 Scanning disc 44 is driven by motor 57, the

speed of which bears a certain fixed relationship tothe film driving mechanisms and also to the speed of the motor 24 at the transmitting station.

the film moving mechanisms is controlled by the speed of the motors 24 and 57 and means Any .suitable synchronizing system may be used. Preferably the speed of Patent No. 1,763,909, of H. M. Stoller ...d E. R. Morton, issued Julie'17, 1930.

A light valve suitable for use in this system is disclosed in Patent No. 1,667,805 issued May 1, 1928, to H. E. Ives.

. An alternative arrangement for variably illuminating the right-hand face of scanning disc 44 in accordance with received image currents is illustrated in Fig. 5. In place of light valves 8, 9 and 10, controlling-the light from steady sources 41, 42 and 43 respectively, discharge lamps 58, 59 and 60 are employed.

These lamps are energized by image currents fromwhannels L ,L and L respectively. The discharge lamps 58, 59 and 60 should I produce light having a 'good actinic charactertistic.

While three channels only are illustrated in the drawing, a larger number of channels may beemployed if the results to'be obtained Warrant such increase. It is to be understood that various modifications of the specific systemsdisclosed come within the purview of this invention, the scopeof which is defined in the appended claims.

What is claimed is:

1. A system for producing successive images-of a field' in which the objects may be moving or changing, comprising means for successively impressing .views of the field upon a record, means controlled simultaneously by separate portions of said record and operating simultaneously with said first means for producing said images,and meansto maintain a fixed motional relationsbe tween'said recording means and said image producing means.

2. Means for scanning afield to setup television image currents comprising a photographic film, means for impressing successive views of the field upon said film to produce frames, driving means therefor, means for developingsaid film, means for scanning s1- multan'eously a plurality of developed frames, means for driving said scanning means, and means for maintaining a fixed motional relation between both said driving means.

3. In a system for clectrically'producing tion. picture film, means to scan simultaneously a plurality of frames of a motion plcture film, means to transmit currents representative of said scannings over separate transmission channels respectively, and means to produce anothermotion picture film in accordance with the transmitted currents substantially like the originally scanned, film. producing successive 4. A system for images at a rate suflicient; to produce a motion picture of a field in which the-objects may be moving or changing, comprising a plurality of transmission channels, means for storing signals representative of said images, certain of which signalsare received from each .channel and at a rate slower than that ing in accordance with said stored signals successive images in the proper rate to of said field.

5. A system for producing successive imagesat-a rate suflicient to produce a motion picture of a may be moving or changing, plurality of transmission channels, means for storing signals representative of said images, certain of which signals arereceived from each channel and at a rate slower than that required for viewing, means for producing in accordance with said stored signals successive images in proper sequence and at the proper rate to produce a motion picture of said field, and means for'maintaining a fixed relationship between said signal storing and proper sequence and at produce a motion picture said image producing means.

I 6. A television system comprising a plurality of transmission channels for sequences of signals representative of successive images of a' scene, a plurality of sequences being transmitted simultaneously over said plurality of channels respectively, means for stor ing each sequence at a rate-slower than that required for viewing successive images of a motion picture, and means for producing in accordance with said stored signals successive images in proper sequence and at the proper rate to produce a motion picture of said scene.

7. A television system comprising a plurality of transmission channels for sequences of signals representative of successive images of a scene, a plurality of sequences being transmitted ceived simultaneously over said plurality of channels, means for producing successive simultaneously over said pluraL ity of channels respectively,-means for stor-' field in which the objects comprising a images from said record at-such a rate that successive images follow each other within the time interval of, persistence of vision, and means to maintain at constant value the average length of recording member between. said-recording means and said image producmg means.

9. In a television system, means to produce image currents corresponding to successive aspects ofan object field, means comprising a velopmg, and image producing means storing slgnals representative of impulses of the period of storage frames, driving means therefor,

, cessive aspects, means tion picture,

' motion picture film,

' picture film,

plurality of simultaneously operating transmission channelsfor the transmission of said currents, a motion picture'film blank, means to expose'said film under the con't-rolof the image currents of said channels to produce successiv'eirames corresponding to said sucto develop said film, means-to produce successive images ofxa'm'oandmean'sto maintain a fixed time relationship between said exposing, de-

10. In asystem for electrically producing means toscan simulta 'neously a plurality of frames of a motion and means to produce image currents representive of said scannings.

11. In a'system for electrically producing motion picture film, plurality of sets of scanning apertures for si- 7 multaneously scanning a plurality of frames of a motion picture film, means to'transmit image currents representative of said scannings over separate transmission channels respectively, a plurality of light controlling devices controlled by the image currents from said transmission channels, and another similar scanning disc for controlling light from said devices to produce another motion picture film like the originally scanned film.

' 12.- Means for scanning a field to set up television image currents comprlsing a photographic film, means for impressing successive views of the field upon said film means for developing said film, a scanning; disc having a plurality of sets ofspirally arranged apertures for scanning simultaneously a plurality the period of persistence.

' nels,

of developed frames, means for driving sa1d scanning disc, and means fixed motional relation between driving means.

13. A method of television which comboth said prises receiving complete sets of image impulses representing complete scanmngs 'respectively at the transmitter, simultaneously a plurality of said sets, of complete sets of impulses being greater than the period of persistence of vision, and at once producing in accordance with said stored signals successive images one duction of each image being no gre ter t an 14. In a television system,

transmission channels, means for storing signals received simultaneously over said chanand means controlled by said stored signals for projecting successive images at the proper intervals to produce motion pictures. In witness whereof, I hereunto subscribe my name-this 21st day of May, 1929.

a scanning disc having a to produce for maintaining a for each set of signals, the period required fo the roa plurality of osarn w. HORTON- 

